TDA4657T [NXP]
Generic multi-standard decoder; 通用的多标准解码器
| 型号： | TDA4657T |
| 厂家： | 
NXP |
| 描述： | Generic multi-standard decoder |
| 文件： | 总17页 (文件大小：121K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
INTEGRATED CIRCUITS
DATA SHEET
TDA4657
Generic multi-standard decoder
June 1993
Preliminary specification
File under Integrated Circuits, IC02
Philips Semiconductors
Preliminary specification
Generic multi-standard decoder
TDA4657
FEATURES
GENERAL DESCRIPTION
• Low voltage (8 V)
The TDA4657 is a monolithic integrated multi-standard
colour decoder for PAL, SECAM and NTSC 4.43 MHz with
negative colour difference output signals. It is adapted to
the integrated baseband delay line TDA4660/61.
• Low power dissipation (250 mW)
• Automatic standard recognition
• No adjustments required
• Reduced external components
• Not all time constants integrated
(ACC, SECAM de-emphasis).
QUICK REFERENCE DATA
SYMBOL
Supply
PARAMETER
CONDITIONS
MIN. TYP. MAX. UNIT
VP
IP
supply voltage
supply current
7.2
VP = 8.0 V; without load 25
8.0
31
8.8
37
V
mA
mW
Ptot
total power dissipation
VP = 8.0 V; without load
−
248 296
Inputs
V9
chrominance input voltage
(peak-to-peak value)
note 1
20
200 400
mV
V
V20
sandcastle input voltage
−
−
13.2
Outputs
V1
colour difference output signals
(peak-to-peak value)
independent of supply voltage; note 2
−(R−Y) output PAL and NTSC 4.43 MHz
442
950
559
525 624
mV
SECAM
1050 1150 mV
665 791 mV
V3
−(B−Y) output PAL and NTSC 4.43 MHz
SECAM
1200 1330 1460 mV
Notes to the quick reference data
1. Within 2 dB output voltage deviation.
2. Burstkey width 4.3 µs
Burst width 2.25 µs,
ratio burst chrominance amplitude 1/2.2.
ORDERING INFORMATION
EXTENDED
PACKAGE
TYPE NUMBER
PINS
PIN POSITION
MATERIAL
plastic
CODE
TDA4657
20
20
DIL
SO
SOT146(1)
SOT163A(2)
TDA4657T
plastic
Note
1. SOT146-1; 1996 November 26.
2. SOT163-1; 1996 November 26.
June 1993
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Philips Semiconductors
Preliminary specification
Generic multi-standard decoder
TDA4657
June 1993
3
Philips Semiconductors
Preliminary specification
Generic multi-standard decoder
TDA4657
PINNING
SYMBOL PIN
DESCRIPTION
−(R−Y)O
DEEM
−(B−Y)O
CFOB
GND
IREF
1
colour difference signal output −(R−Y)* for baseband delay line
external capacitor for SECAM de-emphasis
colour difference signal output −(B−Y)* for baseband delay line
external capacitor SECAM demodulator control (B−Y) Channel
ground
2
3
4
5
6
external resistor for SECAM oscillator
supply 8 V
VP
7
CFOR
CHRI
CACC
HUE
NIDT
8
external capacitor SECAM demodulator control (R−Y) Channel
chrominance signal input
9
10
11
12
13
14
15
16
17
18
19
20
external capacitor for ACC control
input for HUE control and service switch
external capacitor for identification circuit (NTSC)
external capacitor for identification circuit (PAL and SECAM)
PAL crystal
PIDT
OSC
PLL
external loop filter
2FSC
No
2 × fsc output
standard setting input/output for NTSC 4.43
standard setting input/output for SECAM
standard setting input/output for PAL
sandcastle input
SECo
PALo
SC
Fig.2 Pin configuration.
4
June 1993
Philips Semiconductors
Preliminary specification
Generic multi-standard decoder
TDA4657
the (R−Y) Channel. The required reference signals (fsc)
are input from the reference oscillator. In NTSC mode the
PAL switch is disabled.
The SECAM demodulator consists of a PLL system.
During vertical blanking the PLL oscillator is tuned to the
f0 frequencies to provide a fixed black level at the
demodulator output. During demodulation the control
voltages are stored in the external capacitors at pins 4
and 8.
The oscillator requires an external resistor at pin 6. Behind
the PLL demodulator the signal is fed into the de-emphasis
network which consists of two internal resistors
(2.8 kΩ and 5.6 kΩ) and an external capacitor connected
at pin 2 (220 pF).
FUNCTIONAL DESCRIPTION
The IC contains all functions required for the identification
and demodulation of signals with the standards PAL,
SECAM and NTSC 4.3 with 4.43 MHz colour-carrier
frequency. When an unknown signal is fed into the input,
the circuit has to detect the standard of the signal, and has
to switch on successively the appropriate input filter and
demodulator and finally, after having identified the signal,
it has to switch on the colour and, in event of NTSC
reception, the hue control. At the outputs the two colour
difference signals −(R−Y)* and −(B−Y)* are available.
ACC stage
After demodulation the signal is filtered and then fed into
the next stage.
The chrominance signal is fed into the asymmetrical input
(pin 9) of the ACC stage (Automatic Colour Control). The
input has to be AC coupled and has an input impedance of
20 kΩ in parallel with 10 pF.
Blanking, colour killer, buffers
To control the chrominance amplitude the modulation
independent burst amplitude is measured during the
burstkey pulse which is derived from the sandcastle pulse
present at pin 20. The generated error current is fed into
an external storage capacitor at pin 10. The integrated
error voltage controls the gain of the ACC stage so that its
output is independent of input signal variations.
As a result of using only one demodulator in SECAM mode
the demodulated signal has to be split up in the (B−Y)
Channel and the (R−Y) Channel. The unwanted signals
occurring every second line, (R−Y) in the (B−Y) Channel
and (B−Y) in the (R−Y) Channel, have to be blanked. This
happens in the blanking stage by an artificial black level
being inserted alternately every second line.
To avoid disturbances during line and field flyback these
parts of the colour differential signals are blanked in all
modes.
When no signal has been identified, the colour is switched
off (signals are blanked) by the colour killer.
At the end of the colour channels are low-ohmic buffers
(emitter followers). The CD output signals −(B−Y)* and
−(R−Y)* are available at pins 1 and 3.
The measurement is disabled during the vertical blanking
to avoid failures because of missing burst signals.
Reference signal generation
The reference signal generation is achieved by a PLL
system. The reference oscillator operates at twice the
colour-carrier frequency and is locked on the burst of the
chrominance signal (chr). A divider provides reference
signals (fsc) with the correct phase relationship for the
PAL/NTSC demodulator and the identification part. In the
SECAM mode the two f0 frequencies are derived from the
PAL crystal frequency by special dividers. In this mode the
oscillator is not locked to the input signal. In the NTSC
mode the hue control circuit is switched between ACC
stage and PLL. The phase shift of the signal can be
controlled by a DC voltage at pin 11. The hue control circuit
is switched off during scanning.
Identification and system control
The identification part contains three identification
demodulators.
The first demodulates in PAL mode. It is only active during
the burstkey pulse. The reference signal (fsc) has the
(R−Y) phase.
The second demodulator (PLL system) operates in
SECAM mode and is active also during the burstkey pulse,
but delayed by 2 µs.
The PLL demodulator discriminates the frequency
difference between the unmodulated f0 frequencies of the
incoming signal (chr) and the reference frequency input
from the crystal oscillator.
The reference frequency (2 × fsc) is available at pin 16 to
drive a PAL comb filter for example.
Demodulation
The demodulation of the colour signal requires two
demodulators. One is common for PAL and NTSC signals,
the other is for SECAM signals.
The PAL/NTSC demodulator consists of two synchronized
demodulators, one for the (B−Y) Channel and the other for
These two demodulators are followed by an H/2 switch
‘rectifying’ the demodulated signal. The result is an
identification signal (PIDT, pin 13) that is positive for a PAL
signal in PAL mode, for a SECAM signal in SECAM mode
June 1993
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Philips Semiconductors
Preliminary specification
Generic multi-standard decoder
TDA4657
and for a PAL signal in NTSC 4.4 mode. If PIDT is positive
in SECAM mode, the scanner switches back to the PAL
mode in order to prevent a PAL signal being erroneously
identified as a SECAM signal (PAL priority).
If then PIDT is not positive, the scanner returns to SECAM
mode and remains there if PIDT is positive again. In the
event of a field frequency of 60 Hz the signal can not be
identified as a SECAM signal, even if PIDT is positive. In
this event the scanner switches forward in the NTSC 4.4
mode. If the H/2 signal has the wrong polarity, the
identification signal is negative and the H/2 flip-flop is set
to the correct phase.
The third demodulator operates in NTSC mode and is
active during the burstkey pulse. The resulting
identification signal (NIDT, pin 12) is positive for PAL and
NTSC 4.4 signals in NTSC 4.4 mode. The reference signal
has the (B−Y) phase.
pins 17, 18 and 19. During scanning the HIGH level is
2.5 V and when a signal has been identified the HIGH level
is switched to 6 V. The standard pins can also be used as
inputs in order to force the IC into a desired mode (Forced
Standard Setting).
Sandcastle detector and pulse processing
In the sandcastle detector the super sandcastle pulse (SC)
present at pin 20 is compared with three internal threshold
levels by means of three differential amplifiers. The
derived signals are the burstkey pulse, the horizontal
blanking pulse and the combined horizontal and vertical
blanking pulse. These signals are processed into various
control pulses required for the timing of the IC.
Bandgap reference
The two identification signals allow an unequivocal
identification of the received signal. In the event of a signal
being identified, the scanning is stopped and after a delay
time the colour is switched on.
In order to ensure that the CD output signals and the
threshold levels of the sandcastle detector are
independent of supply voltage variations a bandgap
reference voltage has been integrated.
The standard outputs (active HIGH) are available at the
LIMITING VALUES
In accordance with the Absolute Maximum Rating System (IEC 134).
SYMBOL
PARAMETER
CONDITIONS MIN.
MAX.
UNIT
°C
Tstg
Tamb
VP
storage temperature
−25 +150
operating ambient temperature
supply voltage
0
−
−
−
−
+70
°C
V
8.8
Ptot
V20
power dissipation
without load
330
mW
V
voltage at pin 20
Imax = 10 µA
15
voltage at all other pins
Imax = 100 µA
VP + vbe
V
THERMAL RESISTANCE
SYMBOL
PARAMETER
THERMAL RESISTANCE
Rth j-a
thermal resistance on printed-circuit board from junction to
ambient in free air (without heat spreader)
SO 20
DIL 20
90 K/W
70 K/W
June 1993
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Philips Semiconductors
Preliminary specification
Generic multi-standard decoder
TDA4657
CHARACTERISTICS
Measured with application circuit (Fig.4) at Tamb = +25 °C, 8 V supply, 75% colour bar chrominance input signal of
200 mV (peak-to-peak value) and nominal phase for NTSC unless otherwise specified. All voltages measured
referenced to ground.
SYMBOL
PARAMETER
CONDITIONS
MIN.
7.2
TYP.
8.0
MAX.
8.8
UNIT
VP
I
supply voltage
supply current
V
VP = 8.0 V without
load
25
31
37
mA
Ptot
total power dissipation
VP = 8.0 V without
load
−
248
296
mW
CD signals outputs (pins 1 and 3)
PAL or NTSC
V1
colour difference output signals
independent of supply voltage; note 1
−(R−Y) output PAL and NTSC 4.43 MHz
(peak-to-peak value)
442
559
0.75
525
665
0.79
624
791
0.83
mV
mV
−
V3
−(B−Y) output PAL and NTSC 4.43 MHz
(peak-to-peak value)
V1/V3
m
ratio of CD signal amplitudes
note 2
V(R−Y)/V(B−Y)
signal linearity −(R−Y) output
signal linearity −(B−Y) output
cut-off frequency (both outputs)
chrominance delay time
V1 = 0.8 V (p-p)
V3 = 1.0 V (p-p)
−3 dB
0.8
0.8
−
−
−
−
−
−
−
fg
1
−
MHz
ns
dB
td
220
40
270
−
320
−
S/N
signal to noise ratio for nominal output
voltages
note 3
V1, V3
residual carrier at CD outputs
1 × subcarrier frequency
(peak-to-peak value)
−
−
10
mV
2 × subcarrier frequency
(peak-to-peak value)
−
−
−
−
30
10
mV
mV
H/2 content at R−Y output at nominal input
signal (peak-to-peak value)
A
crosstalk between CD Channels
output resistance (npn emitter follower)
output current
−40
−
−
−
−
−
dB
Ω
R1, R3
I1, I3
200
−3
−
mA
June 1993
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Philips Semiconductors
Preliminary specification
Generic multi-standard decoder
TDA4657
SYMBOL
PARAMETER
CONDITIONS
MIN.
TYP.
MAX.
UNIT
SECAM
V1
colour difference output signals
−(R−Y) output (peak-to-peak value)
−(B−Y) output (peak-to-peak value)
independent of supply voltage; note 4
0.95
1.20
0.75
1.05
1.33
0.79
1.15
V
V
−
V3
1.46
0.83
V1/V3
ratio of CD signal amplitudes
V(R−Y)/V(B−Y)
m
signal linearity at nominal output voltage
cut-off frequency
0.8
−
−
−
−
fg
−3 dB
730
500
−
−
kHz
ns
td
chrominance delay time
400
40
600
−
S/N
signal to noise ratio for 100 mV (p-p) input note 3
signal and nominal output voltages
dB
V1, V3
residual carrier at CD outputs:
1 × subcarrier frequency
(peak-to-peak value)
−
−
10
mV
2 × subcarrier frequency
(peak-to-peak value)
−
−
−
−
0
0
20
mV
mV
mV
∆V3
∆V1
shift of demodulated f0 level relative to
blanking level −(B−Y) output
note 8
±13
±10
−(R−Y) output
Impedance and currents see PAL or NTSC specification
Capacitor for SECAM de-emphasis (pin 2)
C2
RA
RB
value of external capacitor
−
220
2.8
5.6
−
−
pF
kΩ
kΩ
%
value of internal de-emphasis resistors
Tamb = 35 °C
2.4
4.8
−
3.2
6.4
±5
∆(RA/RB) relative tolerance of de-emphasis resistors
Capacitors for SECAM demodulator control (pins 4 and 8; note 5)
∆V1, 3
shift of demodulated f0 level due to
external leakage current
Cext = 220 nF
−
−
0.3
mV/nA
Resistor for SECAM oscillator (pin 6)
V6
R6
C6
DC voltage
2.4
−
2.81
5.62
10
3.2
−
V
value of external resistor (±1%)
value of external capacitor (±20%)
kΩ
nF
−
−
Chrominance input (pin 9)
V9
R9
C9
input signal (peak-to-peak value)
note 6
20
16
−
200
20
−
400
24
mV
kΩ
pF
input resistance
input capacitance
10
Capacitor for ACC (pin 10; note 7)
∆V1, 3
change of CD output signals during field
blanking due to external leakage current
Cext = 100 nF
−
0.2
−
%/nA
June 1993
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Philips Semiconductors
Preliminary specification
Generic multi-standard decoder
TDA4657
SYMBOL
PARAMETER
CONDITIONS
MIN.
TYP.
MAX.
UNIT
Hue control (NTSC) and service switch (pin 11)
φ
phase shift of reference carrier
relative to phase at open-circuit pin 11
V11 = 3 V
−30
−
0
−
−
degree
degree
degree
V
V
11 = open-circuit
11 = 5 V
−5
+5
−
V
+30
3.8
V11
R11
internal bias voltage
(proportional to supply voltage)
pin 11 open-circuit
4.0
4.2
input resistance
25
30
35
kΩ
Capacitor for identification (pins 12 and 13)
V12, V13
DC voltage for an identified signal
DC voltage for an unidentified signal
2.8
1.5
3.2
2.0
3.5
2.3
V
V
PLL oscillator measured with nominal crystal (pin 14; see Table 1)
R14
C14
∆fL
initial oscillator amplifier input resistance
oscillator amplifier input capacitance
−500
−
−
−
−
−
Ω
10
pF
Hz
lock-in-range referenced to
4.43361875 MHz
note 9
±400
±1300
φ
phase difference for ±400 Hz deviation of
−
−
1
degree
colour carrier frequency
2 x fsc output (pin 16; if the output is not used, the pin should be connected to supply)
V16
R16
I16
DC output level
I16 = 0 A
I16 = 0 A
6.1
−
6.3
−
6.5
350
−1.0
−
V
output resistance
Ω
output current
−
−
mA
mV
V16
output signal (peak-to-peak value)
−
250
Standard setting inputs/outputs (pins 17 to 19; note 10)
used as output: npn emitter follower output with 0.1 mA source to ground
VO
on-state, during scanning, colour OFF
on-state, colour ON
2.3
5.8
−
2.5
6.0
−
2.7
6.2
300
−3
V
V
RO
IO
output resistance
IO = 0
Ω
output current
−
−
mA
used as input: forced system switching
VO
IO
threshold for system ON
input current
6.8
7.0
7.2
V
100
150
180
µA
June 1993
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Philips Semiconductors
Preliminary specification
Generic multi-standard decoder
TDA4657
SYMBOL
PARAMETER
CONDITIONS
MIN.
TYP.
MAX.
UNIT
Sandcastle pulse detector (pin 20; note 11)
C20
V20
input capacitance
−
−
10
pF
thresholds for field and line pulse
separation
pulse ON
1.3
1.1
3.3
3.1
5.3
5.1
1.6
1.4
3.6
3.4
5.6
5.4
1.9
1.7
3.9
3.7
5.9
5.7
V
V
V
V
V
V
pulse OFF
pulse ON
pulse OFF
pulse ON
pulse OFF
line pulse separation
burst pulse separation
System control processing (note 12)
td
system hold delay
in event of a signal
disappearing for a
short time
2
−
3
field
periods
colour killer; colour ON delay
colour OFF delay
switching occurs
during field blanking
2
0
−
−
−
4
3
1
−
field
periods
field
periods
ts
scanning time for each system
field
periods
QUALITY SPECIFICATION: URV-4-2-59/601
Notes to the characteristics
1. Burstkey width 4.3 µs.
Burst width 2.25 µs, ratio burst chrominance amplitude 1/2.2.
2. At nominal phase of hue control.
3. V (p-p) of signal divided by 6 times effective noise voltage.
4. H/2 blanking alternately every second line.
5. These pins are leakage current sensitive. Pin 4 for (B−Y) Channel, pin 8 for (R−Y) Channel.
6. Within 2 dB output voltage deviation.
7. This pin is leakage current sensitive.
8. IC only.
9. Depends also on network on pin 15.
10. Pin 19 for PAL, pin 18 for SECAM, pin 17 for NTSC 4.43 MHz.
Threshold levels are dependent of supply.
11. The field interval of the sandcastle has to be adapted to the ICs TDA2579B and TDA4690.
The thresholds are independent of supply voltage.
12. System scanning sequence: PAL, SECAM, NTSC 4.4.
June 1993
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Philips Semiconductors
Preliminary specification
Generic multi-standard decoder
TDA4657
Table 1 Specification of quartz crystals in HC-49/U13 holder; standard application.
SYMBOL
PARAMETER
VALUE
UNIT
9922 520 00385
8.867570
series resonance
±20
fn
nominal frequency
load capacitance
MHz
CL
∆fn
adjustment tolerance of fn at +25 °C
ppm
Ω
Rr
resonance resistance over temperature range
≤ 60
Rdld max
in the drive level range between 10−12 W and 1.0 × 10−3 W, the
tbn
Ω
resonance resistance may not exceed (at +25 °C) the value of Rdld max
Rn
resonance resistance of unwanted response
motional capacitance (±20%)
2Rr (+25 °C)
14.0
Ω
C1
fF
C0
parallel capacitance (±20%)
3.6
pF
°C
ppm
Tamb
∆fn
operating ambient temperature
frequency tolerance over temperature
−10 to +60
±20
June 1993
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Philips Semiconductors
Preliminary specification
Generic multi-standard decoder
TDA4657
June 1993
12
Philips Semiconductors
Preliminary specification
Generic multi-standard decoder
TDA4657
June 1993
13
Philips Semiconductors
Preliminary specification
Generic multi-standard decoder
TDA4657
PACKAGE OUTLINES
DIP20: plastic dual in-line package; 20 leads (300 mil)
SOT146-1
D
M
E
A
2
A
A
1
L
c
e
w M
Z
b
1
(e )
1
b
M
H
20
11
pin 1 index
E
1
10
0
5
10 mm
scale
DIMENSIONS (inch dimensions are derived from the original mm dimensions)
(1)
A
A
A
(1)
(1)
Z
1
2
UNIT
mm
b
b
c
D
E
e
e
1
L
M
M
H
w
1
E
max.
min.
max.
max.
1.73
1.30
0.53
0.38
0.36
0.23
26.92
26.54
6.40
6.22
3.60
3.05
8.25
7.80
10.0
8.3
4.2
0.51
3.2
2.54
0.10
7.62
0.30
0.254
0.01
2.0
0.068
0.051
0.021
0.015
0.014
0.009
1.060
1.045
0.25
0.24
0.14
0.12
0.32
0.31
0.39
0.33
inches
0.17
0.020
0.13
0.078
Note
1. Plastic or metal protrusions of 0.25 mm maximum per side are not included.
REFERENCES
OUTLINE
EUROPEAN
PROJECTION
ISSUE DATE
VERSION
IEC
JEDEC
EIAJ
92-11-17
95-05-24
SOT146-1
SC603
June 1993
14
Philips Semiconductors
Preliminary specification
Generic multi-standard decoder
TDA4657
SO20: plastic small outline package; 20 leads; body width 7.5 mm
SOT163-1
D
E
A
X
c
y
H
E
v
M
A
Z
20
11
Q
A
2
A
(A )
3
A
1
pin 1 index
θ
L
p
L
1
10
w
detail X
e
M
b
p
0
5
10 mm
scale
DIMENSIONS (inch dimensions are derived from the original mm dimensions)
A
max.
(1)
(1)
(1)
UNIT
A
A
A
b
c
D
E
e
H
L
L
Q
v
w
y
θ
1
2
3
p
E
p
Z
0.30
0.10
2.45
2.25
0.49
0.36
0.32
0.23
13.0
12.6
7.6
7.4
10.65
10.00
1.1
0.4
1.1
1.0
0.9
0.4
mm
2.65
0.25
0.01
1.27
0.050
1.4
0.25 0.25
0.01
0.1
8o
0o
0.012 0.096
0.004 0.089
0.019 0.013 0.51
0.014 0.009 0.49
0.30
0.29
0.419
0.394
0.043 0.043
0.016 0.039
0.035
0.016
inches 0.10
0.055
0.01 0.004
Note
1. Plastic or metal protrusions of 0.15 mm maximum per side are not included.
REFERENCES
OUTLINE
EUROPEAN
PROJECTION
ISSUE DATE
VERSION
IEC
JEDEC
EIAJ
95-01-24
97-05-22
SOT163-1
075E04
MS-013AC
June 1993
15
Philips Semiconductors
Preliminary specification
Generic multi-standard decoder
TDA4657
method. Typical reflow temperatures range from
215 to 250 °C.
SOLDERING
Introduction
Preheating is necessary to dry the paste and evaporate
the binding agent. Preheating duration: 45 minutes at
45 °C.
There is no soldering method that is ideal for all IC
packages. Wave soldering is often preferred when
through-hole and surface mounted components are mixed
on one printed-circuit board. However, wave soldering is
not always suitable for surface mounted ICs, or for
printed-circuits with high population densities. In these
situations reflow soldering is often used.
WAVE SOLDERING
Wave soldering techniques can be used for all SO
packages if the following conditions are observed:
• A double-wave (a turbulent wave with high upward
pressure followed by a smooth laminar wave) soldering
technique should be used.
This text gives a very brief insight to a complex technology.
A more in-depth account of soldering ICs can be found in
our “IC Package Databook” (order code 9398 652 90011).
• The longitudinal axis of the package footprint must be
DIP
parallel to the solder flow.
• The package footprint must incorporate solder thieves at
the downstream end.
SOLDERING BY DIPPING OR BY WAVE
The maximum permissible temperature of the solder is
260 °C; solder at this temperature must not be in contact
with the joint for more than 5 seconds. The total contact
time of successive solder waves must not exceed
5 seconds.
During placement and before soldering, the package must
be fixed with a droplet of adhesive. The adhesive can be
applied by screen printing, pin transfer or syringe
dispensing. The package can be soldered after the
adhesive is cured.
The device may be mounted up to the seating plane, but
the temperature of the plastic body must not exceed the
specified maximum storage temperature (Tstg max). If the
printed-circuit board has been pre-heated, forced cooling
may be necessary immediately after soldering to keep the
temperature within the permissible limit.
Maximum permissible solder temperature is 260 °C, and
maximum duration of package immersion in solder is
10 seconds, if cooled to less than 150 °C within
6 seconds. Typical dwell time is 4 seconds at 250 °C.
A mildly-activated flux will eliminate the need for removal
of corrosive residues in most applications.
REPAIRING SOLDERED JOINTS
REPAIRING SOLDERED JOINTS
Apply a low voltage soldering iron (less than 24 V) to the
lead(s) of the package, below the seating plane or not
more than 2 mm above it. If the temperature of the
soldering iron bit is less than 300 °C it may remain in
contact for up to 10 seconds. If the bit temperature is
between 300 and 400 °C, contact may be up to 5 seconds.
Fix the component by first soldering two diagonally-
opposite end leads. Use only a low voltage soldering iron
(less than 24 V) applied to the flat part of the lead. Contact
time must be limited to 10 seconds at up to 300 °C. When
using a dedicated tool, all other leads can be soldered in
one operation within 2 to 5 seconds between
270 and 320 °C.
SO
REFLOW SOLDERING
Reflow soldering techniques are suitable for all SO
packages.
Reflow soldering requires solder paste (a suspension of
fine solder particles, flux and binding agent) to be applied
to the printed-circuit board by screen printing, stencilling or
pressure-syringe dispensing before package placement.
Several techniques exist for reflowing; for example,
thermal conduction by heated belt. Dwell times vary
between 50 and 300 seconds depending on heating
June 1993
16
Philips Semiconductors
Preliminary specification
Generic multi-standard decoder
TDA4657
DEFINITIONS
Data sheet status
Objective specification
Preliminary specification
Product specification
This data sheet contains target or goal specifications for product development.
This data sheet contains preliminary data; supplementary data may be published later.
This data sheet contains final product specifications.
Limiting values
Limiting values given are in accordance with the Absolute Maximum Rating System (IEC 134). Stress above one or
more of the limiting values may cause permanent damage to the device. These are stress ratings only and operation
of the device at these or at any other conditions above those given in the Characteristics sections of the specification
is not implied. Exposure to limiting values for extended periods may affect device reliability.
Application information
Where application information is given, it is advisory and does not form part of the specification.
LIFE SUPPORT APPLICATIONS
These products are not designed for use in life support appliances, devices, or systems where malfunction of these
products can reasonably be expected to result in personal injury. Philips customers using or selling these products for
use in such applications do so at their own risk and agree to fully indemnify Philips for any damages resulting from such
improper use or sale.
June 1993
17
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